Florent Prel

Applications of IASI on MetOp-A: first results and illustration of potential use for meteorology, climate monitoring, and atmospheric chemistry

IASI was successfully launched on MetOP A on 19 October 2006. After the in-orbit commissioning, the performances of IASI were evaluated during the Cal/Val of level 1. Key parameters of instrument and on ground processing have been fixed for optimal performance and best quality data delivery. The first spectra and images of level 1 products show all the potential of IASI data for expected applications. Some illustrations are given here with maps of pseudo channels sensitive to trace gases, atmospheric profiles or maps of surface temperature qualitatively compared to maps from models. Level 2 processing to get these parameters has been implemented at Eumetsat and some products are currently under validation. The quality of IASI data paves the way to additional very promising products. A thorough analysis of cloud free spectra has been performed to extract the small signature of minor species like CFCs and HNO3. Nevertheless, the main limitation of IASI data remains clouds. It is showed here with the cluster analysis of AVHRR data registered in the IASI pixels and delivered as level 1 products that only a few cloud free pixels can used for full retrieval. A method making use of the cluster information has been developed. It permits to strongly increase the statistics where clear column profiles or columns above clouds can be retrieved. This scheme will be applied to the retrieval of the CO2 where large data set are needed to extract information from the spectra.

A novel multipixel imaging differential standoff chemical detection sensor

ABB Bomem is expanding its line of infrared remote sensing products with the addition of a new multipixel imaging spectroradiometer. This hyperspectral instrument is based on the proven MR spectroradiometers. The instrument is modular and support several configurations. One of its configurations is optimised for differential acquisition in the VLWIR (cut-off near 14 μm) to support research related to the stand-off detection and quantification of chemicals. In that configuration, the instrument is equipped with a dualinput telescope to perform optical background subtraction. The resulting signal is the differential between the spectral radiance entering each input port.

A broadband field portable reflectometer to characterize soils and chemical samples

The developments of optical methods to characterize soils and various surface contaminants require complete and reliable databases of spectral signatures of various objects, including chemical and representative background surfaces. Ideally, the databases should be acquired in the field to properly consider the chemical mixing and heterogeneity of the surfaces. Spectral characterization instruments are common in the visible and the shortwave infrared but there are few solutions in the midwave and thermal infrared regions. ABB recently developed a broad band reflectometer based on a small FTIR spectrometer. It is capable of measuring diffuse spectral reflectance from various surfaces in the infrared from 0.7 to 13.5 microns. This sensor has been developed to be operated in the field by one person. It is lightweight (about 12 kg); it is battery powered and ruggedized for operation in harsh environments. Its operation does not require sophisticated training; it has been designed to be operated by a non-specialist. The sensor can be used to generate spectral libraries or to perform material identification if a spectral library already exists. Examples of measurements in the field will be presented.

MRi dual-band MWIR imaging FTS

MR-i is an imaging version of the ABB Bomem MR Fourier-Transform spectroradiometer. This field instrument generates spectral datacubes in the MWIR and LWIR. It is designed to be sufficiently fast to acquire the spectral signatures of rapid events. The design is modular. The two output ports of the instrument can be populated with different combinations of detectors (imaging or not). For instance to measure over a broad spectral range, one output port can be equipped with a LWIR camera while the other port is equipped with a MWIR camera. No dichroics are used to split the bands, hence enhancing the sensitivity. Both ports can be equipped with cameras serving the same spectral range but set at different sensitivity levels in order to increase the measurement dynamic range and avoid saturation of bright parts of the scene while simultaneously obtaining good measurement of the faintest parts of the scene. Various telescope options are available for the input port. Overview of the instrument capabilities will be presented. Test results and results from field trials for a configuration with two MWIR cameras will be presented. That specific system is dedicated to the characterization of airborne targets. The two MWIR cameras are used to expand the dynamic range of the instrument and simultaneously measure the spectral signature of the cold background and of the warmest elements of the scene (flares, jet engines exhausts, etc.).

Standoff chemical D and Id with extended LWIR hyperspectral imaging spectroradiometer

Standoff detection and identification (D and Id) of unknown volatile chemicals such as chemical pollutants and consequences of industrial incidents has been increasingly desired for first responders and for environmental monitoring. On site gas detection sensors are commercially available and several of them can even detect more than one chemical species, however only few of them have the capabilities of detecting a wide variety of gases at long and safe distances. The ABB Hyperspectral Imaging Spectroradiometer (MR-i), configured for gas detection detects and identifies a wide variety of chemical species including toxic industrial chemicals (TICs) and surrogates several kilometers away from the sensor. This configuration is called iCATSI for improved Compact Atmospheric Sounding Interferometer. iCATSI is a standoff passive system. The modularity of the MR-i platform allows optimization of the detection configuration with a 256 x 256 Focal Plane Array imager or a line scanning imager both covering the long wave IR atmospheric window up to 14 μm. The uniqueness of its extended LWIR cut off enables to detect more chemicals as well as provide higher probability of detection than usual LWIR sensors.

Modular hyperspectral imager enables multiple research applications

The MR-i spectroradiometer can support a wide range of applications from its architecture suited to multiple configurations. Its modular 4-port FTIR spectroradiometer architecture allows the simultaneous use of two different detector modules, direct or differential input(s) and multiple telescopes. In a given configuration, MR-i can combine a MWIR focal plane array and a LWIR focal plane array to provide an extended spectral range from the two imaging sensors. The two detector array modules are imaging the same scene allowing synchronized pixel-to-pixel spectral range combination. In another configuration, MR-i can combine two identical focal plane arrays with different attenuation factors and two interleaved integration times per detector array. This configuration generates four sets of hyperspectral data cubes with different dynamic ranges that can be combined to produce a single hyperspectral cube with unmatched dynamic range. This configuration is particularly well suited for high-speed, high-dynamic range characterization of targets such as aircrafts, flares, and explosions. In a third configuration, named iCATSI, the spectroradiometer is used in differential input configuration to provide efficient optical background subtraction. The iCATSI configuration features an MCT detectors array with spectral cutoff near 14 µm. This extended spectral range and high sensitivity allows the detection and identification of a wide range of chemicals.

Real time standoff gas detection and environmental monitoring with LWIR hyperspectral imager

MR-i is a dual band Hyperspectral Imaging Spectro-radiometer. This field instrument generates spectral datacubes in the MWIR and LWIR. MR-i is modular and can be configured in different ways. One of its configurations is optimized for the standoff measurements of gases in differential mode. In this mode, the instrument is equipped with a dual-input telescope to perform optical background subtraction. The resulting signal is the differential between the spectral radiance entering each input port. With that method, the signal from the background is automatically removed from the signal of the target of interest. The spectral range of this configuration extends in the VLWIR (cut-off near 14 μm) to take full advantage of the LW atmospheric window.

MR-i: high-speed dual-cameras hyperspectral imaging FTS

From scientific research to deployable operational solutions, Fourier-Transform Infrared (FT-IR) spectroradiometry is widely used for the development and enhancement of military and research applications. These techniques include targets IR signature characterization, development of advanced camouflage techniques, aircraft engines plumes monitoring, meteorological sounding and atmospheric composition analysis such as detection and identification of chemical threats. Imaging FT-IR spectrometers have the capability of generating 3D images composed of multiple spectra associated with every pixel of the mapped scene. That data allow for accurate spatial characterization of targets signature by resolving spatially the spectral characteristics of the observed scenes. MR-i is the most recent addition to the MR product line series and generates spectral data cubes in the MWIR and LWIR. The instrument is designed to acquire the spectral signature of various scenes with high temporal, spatial and spectral resolution. The four port architecture of the interferometer brings modularity and upgradeability since the two output ports of the instrument can be populated with different combinations of detectors (imaging or not). For instance to measure over a broad spectral range from 1.3 to 13 μm, one output port can be equipped with a LWIR camera while the other port is equipped with a MWIR camera. Both ports can be equipped with cameras serving the same spectral range but set at different sensitivity levels in order to increase the measurement dynamic range and avoid saturation of bright parts of the scene while simultaneously obtaining good measurement of the faintest parts of the scene. Various telescope options are available for the input port. Overview of the instrument capabilities will be presented as well as test results and results from field trials for a configuration with two MWIR cameras. That specific system is dedicated to the characterization of airborne targets. The expanded dynamic range allowed by the two MWIR cameras enables to simultaneously measure the spectral signature of the cold background and of the warmest elements of the scene (flares, jet engines exhausts, etc.).

Overview of the iCATSI multi-pixels standoff chemical detection sensor and the MR-i imaging spectroradiometer

ABB Bomem is expanding its line of infrared remote sensing products with the addition of a new imaging spectroradiometer. The instrument is modular and support several configurations. One of its configurations is a multipixels sensor optimised for differential acquisition in the VLWIR to support research related to chemical detection. In that configuration, the instrument is equipped with a dual-input telescope to perform optical background subtraction. The resulting signal is the differential between the spectral radiance entering each input port. The other configuration is a general purpose imaging spectroradiometer designed to acquire the spectral signature of rapid events and fast targets in infrared. Overview of the design and results from tests and first field trials will be presented.

IRCM spectral signature measurements instrumentation featuring enhanced radiometric accuracy

Hyperspectral Infrared (IR) signature measurements are performed in military applications including aircraft- and –naval vessel stealth characterization, detection/lock-on ranges, and flares efficiency characterization. Numerous military applications require high precision measurement of infrared signature characterization. For instance, Infrared Countermeasure (IRCM) systems and Infrared Counter-Countermeasure (IRCCM) system are continuously evolving. Infrared flares defeated IR guided seekers, IR flares became defeated by intelligent IR guided seekers and Jammers defeated the intelligent IR guided seekers [7]. A precise knowledge of the target infrared signature phenomenology is crucial for the development and improvement of countermeasure and counter-countermeasure systems and so precise quantification of the infrared energy emitted from the targets requires accurate spectral signature measurements. Errors in infrared characterization measurements can lead to weakness in the safety of the countermeasure system and errors in the determination of detection/lock-on range of an aircraft. The infrared signatures are analyzed, modeled, and simulated to provide a good understanding of the signature phenomenology to improve the IRCM and IRCCM technologies efficiency [7,8,9]. There is a growing need for infrared spectral signature measurement technology in order to further improve and validate infrared-based models and simulations. The addition of imagery to Spectroradiometers is improving the measurement capability of complex targets and scenes because all elements in the scene can now be measured simultaneously. However, the limited dynamic range of the Focal Plane Array (FPA) sensors used in these instruments confines the ranges of measurable radiance intensities. This ultimately affects the radiometric accuracy of these complex signatures. We will describe and demonstrate how the ABB hyperspectral imaging spectroradiometer features enhanced the radiometric accuracy of spectral signature measurements of infrared military targets.